Blockchain - Proof of Work | Blockchain Tutorial

In this tutorial you will learn about Blockchain – Proof of Work step by step. So without much to do let’s get started.

What is Blockchain?

A blockchain is a continuously developing ledger which continues a permanent record of all the transactions which have taken place in a secure, chronological, and immutable way.

Let’s breakdown the definition,

o Ledger: It is a record this is constantly growing.
O Permanent: It means once the transaction is going internal a blockchain, you can put up it completely within the ledger.

O Secure: Blockchain placed information in a secure way. It uses very advanced cryptography to ensure that the data is locked inside the blockchain.

O Chronological: Chronological means each transaction happens after the previous one.

O Immutable: It method as you construct all the transaction onto the blockchain, this ledger can never be changed.

A blockchain is a chain of blocks which include records. Each block records all of the latest transactions, and as soon as finished goes into the blockchain as a permanent database. Each time a block gets finished, a brand new block is generated.

Note: A blockchain may be used for the secure transfer of money, property, contracts, and so forth. Without requiring a third-party intermediary like bank or government. Blockchain is a software protocol, but it couldn’t be run without the Internet (like SMTP used in email).

Blockchain – Proof of Work

As all transactions are time stamped, we need to put into effect a distributed timestamp server on a peer-to-peer network. This requires some additional implementation and this is the Proof-of-Work that I will describe now. To each block, we now add one more item known as Nonce as shown in the figure below –

Nonce is a number such that the block’s hash meets a sure criterion. This criterion might be that the generated hash must have its leading four digits to be zero.

Thus, the generated hash might look like 000010101010xxx. Generally, the miner begins with a Nonce value of 0 and continues on incrementing it until the generated hash meets the specified criterion.

Note that the hash generation works at random and is beyond your control – that is you can’t pressure the hash characteristic to generate a certain hash. Thus, it may take several iterations till the desired hash with 4 main zeros is generated. The anticipated time for generating a block in bitcoin system is 10 mins. Once the miner correctly mines the block, he releases that within the system making it now the last block within the chain.

Note that there are more than one miners competing to generate the legitimate block. The Bitcoin system awards the primary successful miner by giving him certain bitcoins. In general, the miner with extra computing strength may be an early winner. This can cause attacks at the whole system by those who possess a huge processing energy. We will describe the attacks and how these are mitigated towards the end of this tutorial.